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805ZOOSYSTEMA • 2006 • 28 (4) © Publications Scientifiques du
Muséum national d’Histoire naturelle, Paris. www.zoosystema.com
Taxonomy of tropical West African bivalves. VI. Remarks on
Lucinidae (Mollusca, Bivalvia), with description of six new genera
and eight new species
Rudo von COSELMuséum national d’Histoire naturelle,
Département Systématique et Évolution,Unité Taxonomie et
Collections,
case postale 51, 57 rue Cuvier, F-75231 Paris cedex 05
(France)[email protected]
Key WordsMollusca, Bivalvia,
Lucinidae, tropical West Africa,
deep-sea, zoogeography,
chemosymbionts, new genera, new species.
Cosel R. von 2006. — Taxonomy of tropical West African bivalves.
VI. Remarks on Lucinidae (Mollusca, Bivalvia), with description of
six new genera and eight new species. Zoosystema 28 (4) :
805-851.
AbstrActThirteen species of Lucinidae from continental shelf,
slope and bathyal habitats off tropical West Africa are treated.
Six genera and eight species are described as new: Lamylucina
exgaini n. gen., n. sp. from the infralittoral, Tinalucina
aequatorialis n. gen., n. sp. from the circalittoral W of Bioko
(Fernando Poo) Island, Afrolucina discontinua n. gen., n. sp. from
the lower shelf and upper slope (circalittoral), Lucinoma atalantae
n. sp. from the bathyal of the Cape Verde Basin off Mauritania
(2000 m), Lucinoma myriamae n. sp., Graecina karinae n. gen., n.
sp. and Joellina dosiniformis n. gen., n. sp. from reducing
sediments on the slope off northern Angola and Divaricella
(Egracina) chavani n. sp. from the infralittoral zone. Furthermore,
a new genus, Falsolucinoma n. gen. is introduced for Lucina
leloeuffi Cosel, 1989. Two species of Anodontia Link, 1807,
recently described, are re-included here. Lucinoma vestita
(Dautzenberg & Fischer, 1906) from the upper slope (600 m) at
Cape Verde Islands is rediscussed. Like many other West African
species, the more littoral Afrolucina discontinua n. gen., n. sp.
and Divaricella (E.) chavani n. sp. show distribution gaps along
the West African coast and thus fall into the context of the
hydrographical conditions of this coast.
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806 ZOOSYSTEMA • 2006 • 28 (4)
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InTRoDuCTIon
The Lucinidae are among the six bivalve families which are
presently known as being chemosymbiotic (Schweimanns & Felbeck
1985; Taylor & Glover 2000; Glover et al. 2004); the other
families being Vesicomyidae, Solemyidae, members of the family
Mytilidae (e.g., the genera Bathymodiolus Kenk & Wilson, 1985;
Gigantidas Cosel & Marshall, 2003; and Tamu Gustafson, Turner,
Lutz & Vrijenhoek, 1998), Thyasiridae and Teredinidae (see
Cavanough 1983; Felbeck 1983; Reid & Brand 1986; Fisher 1990;
Reid 1990; Distel & Roberts 1997; Williams et al. 2004 and
further references cited therein). Lucinid species host
chemoautotrophic sulphide-oxidizing bacteria in their gills. They
inhabit a large array of biotopes in depths between the intertidal
zone and more than 2000 m and are mostly associated with dysaerobic
habitats: reducing sediments, often with concentrations of sunken
wood and other plant debris, anoxic black mud, mangrove areas,
dense
roots of seagrass beds (see Glover & Taylor 1997), cold
seeps (okutani & Hashimoto 1997; Salas & Woodside 2002;
this paper) and even hydrothermal vents (Glover et al. 2004).
Although lucinid species are able to feed on particles (Reid &
Slack-Smith 1998), a large part of their nutrition is derived from
endosymbiotic bacteria (Taylor & Glover 2000). This
endosymbiosis is a major reason for the current focus of interest
in the biology of Lucinidae, and, as a consequence, the systematics
and taxonomy of this interesting family attract bivalve researchers
and are the subjects of several recent publications.The Lucinidae
are a much more diverse family than previously thought. The number
of Recent species was estimated at about 250 (Boss 1971), and that
still was the “state of the art” when the last major systematic
revision of the family was published by Bretsky (1976). However,
during the last decade, many new species, subgenera and genera have
been described, mostly but not exclusively from the Indo-West
Pacific biogeographical province, from both
résumé Taxonomie de bivalves d’Afrique occidentale tropicale.
VI. Remarques sur des Lucinidae (Mollusca, Bivalvia), avec
description de six genres nouveaux et huit espèces nouvelles.Sont
traitées 13 espèces de Lucinidae du plateau continental, du talus
et de l’abyssal au large de la côte d’Afrique occidentale
tropicale. Six genres sont introduits et huit espèces nouvelles
sont décrites : Lamylucina exgaini n. gen., n. sp. de
l’infralittoral, Tinalucina aequatorialis n. gen., n. sp. du
circalittoral ouest de l’île de Bioko (Fernando Poo), Afrolucina
discontinua n. gen., n. sp. du plateau inférieur et du talus
supérieur (circalittoral), Lucinoma atalantae n. sp. du bathyal du
Bassin du Cap-Vert au large de la Mauritanie (2000 m), Lucinoma
myriamae n. sp., Graecina karinae n. gen., n. sp. et Joellina
dosiniformis n. gen., n. sp. des sédiments réducteurs sur le talus
au large du nord de l’Angola, et Divaricella (Egracina) chavani n.
sp. de la zone infralittorale. De plus, Falsolucinoma n. gen. est
introduit pour Lucina leloeuffi Cosel, 1989. Deux espèces du genre
Anodontia Link, 1807, récemment décrites, sont incluses ici.
Lucinoma vestita (Dautzenberg & Fischer, 1906) du talus
supérieur (600 m) des Îles du Cap-Vert est rediscuté ici. Comme
beaucoup d’autres espèces ouest-africaines, les espèces Afrolucina
discontinua n. gen., n. sp. et Divaricella (E.) chavani n. sp.
provenant du littoral et du plateau continental présentent des
discontinuités de distribution le long de la côte ouest-africaine,
ainsi rentrent-elles dans le contexte des conditions
hydrographiques de cette côte.
mots clésMollusca, Bivalvia,
Lucinidae, Afrique occidentale tropicale,
eaux profondes, zoogéographie,
chémisymbiontes, genres nouveaux, espèces nouvelles.
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new taxa of tropical West African Lucinidae (Mollusca,
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ZOOSYSTEMA • 2006 • 28 (4)
shallow water (Taylor & Glover 1997a, b, 2002, 2005; Glover
& Taylor 1997, 2001; Glover et al. 2003), and deep water
(okutani & Hashimoto 1997; Salas & Woodside 2002; Bouchet
& Cosel 2004; Glover et al. 2004; Cosel & Bouchet unpubl.
data). Many of these deep water species are unexpectedly large.
Additionally, a considerable number of other species still remains
to be named. So, it seems very unlikely that the statement of Dall
(1901), that Lucinoidea were more species-rich during the Tertiary
than in the Recent, can be supported: the actual number of Recent
species is now estimated at more than 500, the number of fossil,
now extinct species may be in the same order.
After the publication of most of the then un-described marine
bivalve species of tropical West Africa (Cosel 1989, 1990, 1993,
1995; Cosel & Salas 2001; oliver & Cosel 1993a, b; Salas
& Cosel 1991; Salas & Rolan 1991) in preparation of an
identification guide, some new taxa remain undescribed, among
others in the family Lucinidae. Furthermore, several unknown and
mostly large Lucinidae were discovered during recent oceano-graphic
expeditions, most of them from deep water habitats. Thirty-two
species of Lucinidae are now known from tropical West African
waters, they are listed in Appendix. It is remarkable that also in
the Mediterranean, a large lucinid bivalve was discov-ered and
described only very recently (Lucinoma kazani Salas & Woodside,
2002).
In this paper, six new genera are introduced and eight new
species described, among them, one well known species in
clarification of an unclear taxonomic situation. Four of the
species treated here are large species from deep water. Moreover,
five other species are redescribed in detail and placed in the
context of our present knowledge of the Lucinidae.
AbbreviAtionsBMnH The natural History Museum, London;IRD
Institut de Recherche pour le Développement,
Paris (formerly oRSToM);IRSnB Institut royal des Sciences
naturelles de Belgique,
Brussels;MnHn Muséum national d’Histoire naturelle, Paris;MoM
Musée océanographique, Monaco;ZMC universitets Zoologisk Museum,
Copenhagen;lv. left valve;rv. right valve;
sh. dead-collected bivalve specimen;spm live-collected
specimen;v. single valve.
SySTeMATICS
order VeneRoIDA H. Adams & A. Adams, 1856
Superfamily LucinoideA Fleming, 1828 Family LucinidAe Fleming,
1828
Genus Lamylucina n. gen.
type species. — Phacoides (Lucinoma) gaini Lamy, 1920.
species incLuded. — Lamylucina gaini (Lamy, 1920) n. comb.;
Lamylucina exgaini n. sp.
etymoLogy. — In memory of Édouard Lamy, who was the first
“modern” revisor of Lucinidae and who described the type species of
this genus.
distribution. — Tropical West Africa.
diAgnosis. — Shells small, up to 20 mm, subcircular to circular,
very compressed. Beaks small, almost median or slightly in front of
the vertical midline. Surface with fine, more or less widely spaced
to contiguous commarginal ridges or lamellae, some of them becoming
more or less lamellate on the antero- and postero-dorsal margin.
Posterior area delimited by a shallow radial depression. Lunule
very short and broad, escutcheon very long and narrow. Inner margin
smooth. Hinge with one small cardinal tooth in the right valve and
two in the left valve, often very weak to almost obsolete. no
lateral teeth. Ventral prolongation of the anterior adductor scar
rather long but small and narrow.
remArksThis genus is distinguished from other Lucinidae by the
extremely flat valves, the long but narrow diverging part of the
anterior adductor scar, the small umbo, the regular commarginal
sculpture and the more or less leafy prolongations of the
commarginal ridges on the dorsal margin. The most closely similar
genus may be Lamellolucina Taylor & Glover, 2002, which has
more tumid shells, more widely spaced lamellae, a crenulate margin
and a shorter diverging part of the anterior adductor scar. That
genus is mainly Indo-Pacific with L. reyrei (nicklès, 1955) being
the only tropical West African species.
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Table 1. — Lamylucina gaini (Lamy, 1920) n. comb.: selected
measurements (in mm) and length/height ratio. All non type
specimens are voucher specimens.
Shell length × height × tumidity Specimen Length/height
ratio15.2 × 14.7 Bissagos, lectotype 1.015.0 × 15.2 Guinea,
SEDIGUI, stn 362 1.015.0 × 14.2 Guinea, SEDIGUI, stn 82 1.114.9 ×
13.6 Guinea, SEDIGUI, stn 277 1.114.6 × 13.6 Guinea, SEDIGUI, stn
154 1.114.2 × 13.9 Guinea, SEDIGUI, stn 277 1.013.4 × 13.3
Bissagos, paralectotype 1 1.012.6 × 11.4 Guinea, SEDIGUI, stn 367
1.112.0 × 10.9 × 3.6 Guinea, SEDIGUI, stn 368 1.111.8 × 11.4
Bissagos, paralectotype 2 1.08.9 × 8.1 Equatorial Guinea 1.18.2 ×
7.8 Principe, Calypso‚ 1956, stn P 7 1.18.1 × 7.4 Principe,
Calypso‚ 1956, stn P 14 1.18.0 × 7.3 Bissagos, paralectotype 3
1.17.3 × 7.1 Principe, Calypso, 1956, stn P 14 1.0
Lamylucina gaini (Lamy, 1920) n. comb. (Figs 1; 2A; 4)
Phacoides (Lucinoma) gaini Lamy, 1920: 192-194.
type mAteriAL. — The material present in MnHn on which the
description of L. gaini n. comb. is based were not specifically
designated as types, it consists of three right valves and one left
valve from the Bissagos Archipelago (Guinea-Bissau) and one left
valve from Conakry (Guinea), these were to be considered as
syntypes. As Lamy (1920) did not give a precise type locality, and
as the specimen from Conakry belongs to another species (described
in the next entry), the most typical specimen, and not the two
smaller, figured specimens, from the Bissagos Islands lot is here
selected as lectotype, and the other specimens are paralectotypes.
The type locality is the locality cited by Lamy for this lot.
type LocALity. — Passage between Soga and Rouba, Bissagos
Islands, Guinea Bissau.
other mAteriAL exAmined. — Guinea. nearshore continental shelf,
SeDIGuI cruises, 9°03’n-9°48’n, 17-39 m, most taken by bottom grab,
some by dredge, RV André Nizery, X.1988, leg. R. von Cosel, V.1988,
13 lots, sh. and v. (all MnHn).Ilha do Principe. Baia de Santo
Antonio, entrance, 15 m, RV Calypso, Golfe de Guinée, stn P 14,
numerous v. (MnHn). — Between Punta da Mina and Punta novo Destino,
6 m, RV Calypso, Golfe de Guinée, stn P 7, 6 rv., 1 lv. (MnHn). —
Praia de Santo Antonio, RV Calypso, Golfe de Guinée, stn P 22, 2 v.
(MnHn).equatorial Guinea. 01°40’S, 09°25’e, 150 m, in sediment
core, communicated by S. Gofas, 1 rv. (MnHn).Gabon. Cap esterias,
Pointe Idolo, on sandbank,
14.XI.1988, leg. R. von Cosel, 1 small chipped rv. (MnHn).
distribution. — Senegal (Dakar) to Guinea (Sierra Leone border)
and Gabon; Sao Tomé, Ilha do Principe.
descriptionShell small, 9-20 mm, rather thin but appearing
solid, subcircular to circular, almost as long as high
(length/height ratio 1.13-1.15), slightly inequilateral, equivalve,
very compressed. Beaks just in front of the vertical midline.
Anterior part broadly rounded, with a shallow inflexion between the
middle part and the rounded corner to the antero-dorsal margin
which is straight. Postero-dorsal margin slightly convex, posterior
margin rounded, with a more or less indistinct, rounded
postero-dorsal corner. Ventral margin well and evenly rounded.
exterior with regular, fine and thin commarginal lamellae (about
40-55 in large specimens) which on the very early part are more
closely spaced than on the disk. Interspaces smooth. Part of the
lamellae becoming more lamellate to foliate on the antero-dorsal
and postero-dorsal margins. Postero-dorsal area separated by a
rather broad and shallow radial depression. Antero-dorsal area
small, delimited by a sharp groove which also separates the disk
sculpture with commarginal ridges from the foli-ate sculpture.
Hinge plate moderately narrow, right valve with a single small
cardinal tooth, no lateral. Left valve
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new taxa of tropical West African Lucinidae (Mollusca,
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ZOOSYSTEMA • 2006 • 28 (4)
Fig. 1. — Lamylucina gaini (Lamy, 1920) n. comb.: A, lectotype
(here designated), Passage between Soga and Rouba, Bissagos
Islands, Guinea Bissau, 15.2 mm (MNHN), exterior and interior view
of rv.; B, paralectotype 1, same locality, 13.4 mm (MNHN), exterior
of rv.; C, Ilha do Principe, RV Calypso, Golfe de Guinée, stn P 14,
15 m, 7.0 mm, exterior of rv.; D, Guinea, W of Baie de Sangarea,
9°42’N, 14°05’W, 16 m, SEDIGUI, stn 369, 12.0 mm, exterior of both
v., interior of lv., dorsal view.
with one anterior and one posterior simple car-dinal, no
laterals. Lunule very short, broad and heart-shaped, somewhat
assymmetrical, laterally
slightly more prominent in the right valve, deeply inset;
escutcheon long and extremely narrow, al-most nonexistent. Anterior
adductor scar small and
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810 ZOOSYSTEMA • 2006 • 28 (4)
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Fig. 2. — Half schematic drawings of the insides of right
valves: A, Lamylucina gaini (Lamy, 1920) n. comb., lectotype; B, C,
Lamylucina exgaini n. gen., n. sp.; B, holotype; C, Ilha do
Principe, RV Calypso, Golfe de Guinée, stn P 17. Scale bars: 10
mm.
narrow, with moderately long ventral part separate from the
pallial line, this latter meeting the muscle impression almost in
the middle. Inner margin of valves smooth.
Valves entirely white; periostracum not seen.Measurements are
provided in Table 1.
biotopeIn fine, more or less muddy sand, from shallow water to
about 30 m.
remArksLamylucina gaini n. comb. is characterized by the very
flat valves, the commarginal lamellae with
clearly defined interspaces which are broader than the lamellae,
and the well marked prolongations of these lamellae on the
antero-and postero-dorsal keel.
Lamylucina exgaini n. sp. (Figs 2B, C; 3; 4)
Phacoides (Lucinoma) gaini Lamy, 1920: 192-194 (partim).
type mAteriAL. — Holotype: Guinean continental shelf, W of
Kaporo, 9°42’n, 15°21’W, 32 m, RV André Nizery, SeDIGuI, stn 344,
22.V.1988, complete shell (MnHn).
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new taxa of tropical West African Lucinidae (Mollusca,
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ZOOSYSTEMA • 2006 • 28 (4)
Fig. 3. — Lamylucina exgaini n. gen., n. sp.: A, holotype, W of
Kaporo, Guinean continental shelf, 9°42’N, 15°21’W, 32 m, RV André
Nizery, SEDIGUI, stn 344, 22.V.1988, 11.4 mm (MNHN), exterior and
interior of both v., dorsal view; B, paratype, same locality, 13.1
mm (MNHN), exterior of lv.; C, paralectotype of Lucina gaini Lamy,
1920, Conakry, 9.4 mm (MNHN), exterior and interior of lv.; D,
Guinea, W of Île Konebomby, 9°48’N, 15°02.5’W, 33 m, SEDIGUI, stn
399, 16.4 mm, exterior and interior of rv.
Paratype: same locality, 1 rv. (MnHn).
type LocALity. — Kaporo, Guinea.
etymoLogy. — The fact that this species was hitherto always
identified as L. gaini n. comb. is expressed in the name.
other mAteriAL exAmined. — senegal. Dakar region, S of Gorée,
110-112 m, dredged RV Gérard Tréca, 18.II.1954, leg. I.
Marche-Marchad, 1 rv. (MnHn). — Same locality, 95-98 m, 1 lv.
(MnHn). — Dakar region (no details), 129-150 m, dredged RV Gérard
Tréca, 24.I.1958, leg. I.
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812 ZOOSYSTEMA • 2006 • 28 (4)
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Table 2. — Lamylucina exgaini n. gen., n. sp.: selected
measurements (in mm) and length/height ratio. All non type
specimens are voucher specimens.
Shell length × height × tumidity Specimen Length/height
ratio19.4 × 18.2 Ghana, Calypso, 1956, stn 26 1.117.8 × 17.3
Guinea, SEDIGUI, stn 617 1.016.8 × 16.1 Guinea, SEDIGUI, stn 544D
1.016.3 × 16.2 Gabon, Cap Esterias 1.015.7 × 14.7 Guinea, SEDIGUI,
stn 544D 1.115.5 × 14.2 Guinea, SEDIGUI, stn 446 1.115.0 × 14.6
Guinea, SEDIGUI, stn 617 1.014.5 × 13.6 Senegal, Casamance, 40 m,
Louis Sauger 1.114.3 × 14.7 Principe, Calypso, 1956, stn P 17
1.013.5 × 13.3 Senegal, Dakar 1.013.1 × 12.0 Guinea, paratype
1.112.2 × 11.1 São Tomé, Calypso, 1956, stn T 18 1.111.4 × 10.8 ×
4.6 Guinea, holotype 1.19.4 × 9.0 Guinea, Conakry paralectotype of
L. gaini n. comb. 1.08.9 × 8.5 Senegal, Casamance, 40 m, Louis
Sauger 1.0
Marche-Marchad, 1 rv., 1 lv. (MnHn). — n Casamance, 12°44.5’n,
17°37.3’W, 40 m, dredged RV Louis Sauger, III.1988, leg. R. von
Cosel, 1 rv., 1 lv. (MnHn) — n Casamance, Kafountine, 12°57.5’n,
17°16.8’W, 35 m, dredged RV Louis Sauger, III.1988, leg. R. von
Cosel, 3 lv. (MnHn).Guinea-bissau. Southern part, 11°11’n, 16°59’W,
26 m, dredged RV André Nizery, 22.IV.1988, leg. R. von Cosel, 1 rv.
(MnHn).Guinea (conakry). Conakry (no details, paralectotype of
Phacoides gaini Lamy, 1920), 1 lv. (MnHn). — Guinean continental
shelf, SeDIGuI cruises, 9°03’n-10°12’n, 24-57 m, bottom grab or
dredge, RV André Nizery, V.1988 and X.1988, leg. R. von Cosel, 36
lots with numerous sh. and v. (MnHn).sierra leone. off Sherbro
Island, 7°15.5’n, 12°61’W, 64 m, dredged RV Calypso, Golfe de
Guinée, stn 10, 14.V.1956, leg. I. Marche-Marchad, 1 rv., 3 lv.
(MnHn).côte d’Ivoire. Abidjan region (no precision), leg. I.
Marche-Marchad, 1 lv. (MnHn).Ghana. 4°37’n, 0°50’ W, 90-100 m,
dredged RV Calypso, Golfe de Guinée, stn 26, 24.V.1956, leg. I.
Marche-Marchad, 1 rv. (MnHn).Ilha do Principe. off Praia Grande, 12
m, dredged RV Calypso, Golfe de Guinée, stn P 17, 3.VII.1956, leg.
I. Marche-Marchad, 1 rv. (MnHn).são tomé. off Praia Lagarto, 5-6 m,
dredged RV Calypso, Golfe de Guinée, stn T 18, leg. I.
Marche-Marchad, 11.VI.1958, 1 rv. (MnHn).Gabon. Cap esterias,
Pointe Idolo, on sandbank, 14.XI.1988, leg. R. von Cosel, 1 v.
(MnHn). — Port-Gentil, Plage de la Sogara, beachdrift, 11.I.2004,
leg. R. von Cosel, 2 v. (MnHn).
distribution. — Senegal (Dakar region) to Gabon, São Tomé, Ilha
do Principe.
descriptionShell small, 9-20 mm, rather thin but appearing
solid, circular, almost as long as high (length/height ratio
1.0-1.1), slightly inequilateral, equivalve, very compressed. Beaks
about in or just in front of the vertical midline. Anterior part
broadly rounded, with a very shallow inflexion between the middle
part and the rounded corner to the short antero-dorsal margin.
Postero-dorsal margin more or less convex, posterior margin evenly
rounded, with an indistinct, rounded postero-dorsal corner. Ventral
margin rounded.
exterior with more or less irregular, fine, very densely spaced
and thin, rounded commarginal ridges or cords, giving the surface a
somewhat glossy appearance. occasionally narrow, smooth
interspaces. Ridges in the middle part coalescing in some specimens
resulting in some nearly smooth areas. only few of the commarginal
cords may be-come lamellate or somewhat foliate on the
antero-dorsal and postero-dorsal margin. occasionally some deeper
incised growth stages. Postero-dorsal area separated by a broad and
very shallow radial depression. Antero-dorsal area very small and
nar-row, delimited by a sharp groove.
Hinge plate moderately narrow, right valve with a single small
cardinal, no lateral. Left valve with one anterior and one
posterior simple cardinal, no laterals visible. Hinge teeth very
shallow and often reduced to completely missing. Lunule very
small
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Fig. 4. — Distribution of Lamylucina gaini (Lamy, 1920) n. comb.
(★) and Lamylucina exgaini n. gen., n. sp. (●) on the continental
shelf of Guinea. Light grey area marks the sandy-muddy bottom, the
clear area is pure sand, partly with gravel and shell debris.
and heart-shaped, assymmetrical, laterally slightly more
prominent in the right valve, deeply inset; escutcheon almost
nonexistent. Anterior adductor scar very small and narrow, with
moderately long and narrow ventral part separate from the pallial
line, the latter meeting the muscle impression above the middle.
Inner margin of valves smooth.
Valves entirely white; periostracum not seen.Measurements are
provided in Table 2.
biotopeFine and mixed sand, without muddy components, mostly
from about 25 m downward to 150 m, only on the coast of Gabon and
the islands of the Gulf of Guinea in shallower water.
remArksLamylucina exgaini n. gen., n. sp. is similar to L. gaini
n. comb., with which it was previously confused. The principal
difference from L. gaini n. comb. is the external sculpture with
the much more close-set commarginal sculpture consisting of
fine rounded and broader cords rather than ridges or lamellae.
These cords often touch each other or even merge to a certain
extent, whereas in L. gaini n. comb., the lamellae always have more
or less large, clearly defined interspaces. In contrast to L. gaini
n. comb., the leaf-like prolongations of a part of the commarginal
ridges are very much reduced or absent, and the postero-dorsal
margin is often more sloping; with the valves thus appearing
subcircular. The anterior adductor scar, especially its diverging
part is somewhat narrower. The cardinals are less developed and may
be completely absent.
Both species were encountered sympatrically in some places
(Gabon, Ilha do Principe), without intergrades.
During the SeDIGuI cruises on the Guinean shelf, L. gaini n.
comb. was found in more inshore waters on fine sandy substrates but
always with a more or less high portion of mud, whereas L. exgaini
n. gen., n. sp. is confined to more offshore localities, living in
sandy bottom without mud (see Fig. 4). The two species have clearly
different
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sediment preferences, and in certain localities like the Guinean
shelf, they also seem to prefer different depths but this is not
always the case.
Genus Tinalucina n. gen.
type species. — Tinalucina aequatorialis n. sp.
species incLuded. — Tinalucina aequatorialis n. sp.; T. inanis
(Prashad, 1932) n. comb.
etymoLogy. — Dedicated to my colleague Tina Molodtsova in
acknowledgement of her work-up of the collection of antipatharians
of MnHn.
distribution. — Inner Gulf of Guinea, tropical West Africa, and
Indo-West Pacific (Sumbawa, Indonesia).
diAgnosis. — Shells small, mostly under 10 mm, variable in
outline, subcircular, slightly longer than high to almost as long
as high, moderately tumid, with a broad anterior and posterior part
and a more or less truncated, very slightly or not indented
posterior margin. Anterior margin more convex in its middle part.
Beaks in or just in front of the vertical midline. umbones rather
prominent. Surface with more or less developed, densely spaced fine
commarginal lamellae, which may be obsolete on the middle part of
the disk. Antero-dorsal area small and hardly separated, a
depression may be visible. Posterior angle rounded, postero-dorsal
depression broad and shallow but well developed. Lunule small, not
too narrow, only slightly asymmetrical. escutcheon entirely filled
with the ligament. Hinge plate more or less narrow, with slight
vestiges of one or two cardinals. Diverging part of anterior
adductor scar short and broad, with a length of about half the
total length of the scar. Inner margins smooth.
remArksThe species of this genus are characterized by a
combination of features: small size, nearly equal-sized adductor
scars with the short and broad anterior adductor with short
diverging part, well set-off posterior area and somewhat irregular
surface of the valves. The other species in the genus is Tinalucina
inanis n. comb., which was placed in Dentilucina (Dentilucina) by
Prashad (1932). Dentilucina P. Fischer, 1887 (type species: Venus
jamaicensis Spen-gler, 1784), however, is an objective synonym of
Phacoides Agassiz, 1845. The two species united in the new genus
Tinalucina n. gen. demonstrate again a close relationship between
the molluscan fauna
of tropical West Africa and that of the Indo-West Pacific
realm.
Tinalucina aequatorialis n. sp. (Figs 5; 6A, B)
type mAteriAL. — Holotype: equatorial Guinea, W of Bioko Island
(formerly Fernando Poo), off the coast of Cameroon, 3°50’20”n,
8°21’40”e, 98 m, in silty bottom, a fresh empty shell, taken by
corer, Gardline Survey 2003, stn VIo 2, 6.8 × 6.0 × 3.0 mm (BMnH
20040254).
type LocALity. — Bioko (formerly Fernando Poo), equatorial
Guinea.
etymoLogy. — After equatorial Guinea, in which the type locality
is situated.
distribution. — Inner Gulf of Guinea, only known from the type
locality and possibly restricted to the Cameroon deeper shelf and
adjacent islands.
descriptionShell very small (holotype 6.8 mm long), rather thick
and solid, equivalve, moderately inflated, subcircular but more
tending to rectangular-polygonal, slightly longer than high,
length/height ratio 1.1. umbones prominent, beaks slightly in front
of the vertical midline. Antero-dorsal (lunular) margin markedly
concave, antero-dorsal corner narrowly rounded, well marked.
Anterior margin rounded, more so on its middle part, ventral margin
rounded, less convex in its middle part. Posterior margin nearly
vertically truncated, with a very slight sinuosity in the middle
and with broadly rounded postero-dorsal and postero-ventral
corners.
exterior somewhat irregular, with irregularly but mostly
densely-spaced, shallow, commarginal lamellae and a few growth
lines. Anterior angle almost absent, anterior radial depression
obsolete, antero-dorsal area indistinct. Posterior angle rounded,
posterior radial depression broad and well defined, ending in a
very shallow indentation of the posterior margin. Lunule small,
moderately narrow, slightly asymmetric, longer than broad, a little
sunken; escutcheon absent, ligament deeply sunken.
Hinge plate narrow but strong, right valve with a rudimentary
single cardinal tooth, an anterior
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Fig. 5. — Tinalucina aequatorialis n. gen., n. sp., holotype, W
of Bioko Island (formerly Fernando Poo), Equatorial Guinea, off the
coast of Cameroon, 3°50’20”N, 8°21’40”E, 98 m, 6.8 mm (BMNH),
exterior and interior of both v., dorsal view.
lateral and vestiges of a posterior lateral. Left valve with two
small cardinals, an anterior lateral and the vestiges of a
posterior lateral. Anterior adductor scar rather short, with short
and broad diverging part, the pallial line meeting the scar
slightly above its middle. Inner margin smooth.
Valves entirely white, periostracum thin and almost colourless,
eroded on large parts of the valves.
remArksThe only comparable species is the Indo-Pacific T. inanis
n. comb. (see Fig. 6C), which grows only slightly larger than T.
aequatorialis n. gen., n. sp., up to 10 mm; it is further
distinguished by the smooth middle part of the valves, however,
both species share the somewhat irregular valve surface, the
general shell outline, the hinge dentition and the equi-sized
adductor scars. The only other very small tropical West African
lucinid species, Loripes
(Keletistes) legouxi (nicklès, 1952) (Fig. 6D), is easily
distinguished by its internal ligament and its much more tumid
valves. Tinalucina aequatorialis n. gen., n. sp. was found together
with juveniles of Afrolucina discontinua n. gen., n. sp. (described
herein, see below) of about the same size.
Genus Falsolucinoma n. gen.
type And onLy species. — Lucina leloeuffi Cosel, 1989.
etymoLogy. — In spite of the differences, at a first glance and
external view, the valves resemble a Lucinoma, and this is
expressed in the name (falsus, Latin = false).
distribution. — northern Gulf of Guinea, tropical West
Africa.
diAgnosis. — Shells large, subcircular-triangular, compressed,
with short and conspicuously rostrate anterior part and broad and
longer posterior part.
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Fig. 6. — Half schematic drawings of the insides of valves: A,
B, Tinalucina aequatorialis n. gen., n. sp., holotype (BMNH),
interior of lv.; B, interior of rv.; C, Tinalucina inanis (Prashad,
1932) n. comb., holotype (Zoologisch Museum Amsterdam), interior of
lv.; D, Loripes (Keletistes) legouxi (Nicklès, 1952), Côte
d’Ivoire, continental slope (no precision), dredged RV Reine Pokou,
leg. Le Loeuff, interior of rv. (for comparison). Scale bars: A, B,
5 mm; C, 10 mm; D, 2.5 mm.
Anterior and posterior area well demarcated. Surface with 10-15
conspicuous, thin, raised and widely spaced commarginal lamellae
and smooth interspaces. Lunule very small and short, slightly
asymmetric, escutcheon long and deeply sunken, delimited by a keel
and almost entirely filled by ligament. Hinge plate narrow, left
valve with two cardinal teeth, a strong anterior lateral and a
smaller, narrower knob above it, and a narrow posterior lateral;
right valve with two cardinals, two anterior laterals and two
posterior laterals. Ligament short. Adductor scars small for the
shell size, diverging part of anterior adductor scar very short and
rather narrow, tapering; pallial line meeting the scar about in its
middle. Inner margins smooth, but radial wavy sculpture on the zone
between pallial line and margin and occasionally a few vestiges of
irregular crenulations.
remArksThis genus is characterized by the strong anterior and
posterior laterals in both valves, the small anterior adductor scar
with the short and narrow diverging part and the short and rostrate
anterior part of the shell. externally it reminds a Lucinoma, with
which it has in common the toothed hinge and the lamellose exterior
with well separated anterior and posterior areas. There are also
Lucinoma species with rostrate anterior margins (e.g., in this
paper), but to a lesser extent. Moreover, the very much forward
placed umbones, the more conspicuously rostrate anterior margin and
the very small diverging part of the anterior adductor scar clearly
distinguish
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Falsolucinoma n. gen. The highly asymmetric lunule and the short
anterior adductor scar place the genus closer to the Myrtea group;
however, species of Myrtea are smaller and often more tumid with
their characteristicelly raised escutcheonal keel, often with tiny
and dense spines. Their outline is more regular with the umbones
placed less forward.
There is only one other genus known which has a similarly short
and rostrate anterior part and a very short diverging part of the
anterior adductor scar. It occurs in the Indo-West Pacific and will
be pub-lished elsewhere (Cosel & Bouchet unpubl. data). Species
of that genus, however, are more elongate, they have very densely
spaced commarginal lamellae, the diverging lower part of the
anterior adductor scar is much broader, and their hinge plate is
nar-rower and almost toothless.
The genus most similar to Falsolucinoma n. gen. is Lamellolucina
Taylor & Glover, 2002, which is predominantly Indo-West
Pacific, but one species, L. reyrei (nicklès, 1955) occurs in West
Africa. It is also characterized by prominent and more or less
widely spaced commarginal lamellae, a similar hinge dentition with
strong laterals and a gener-ally rather short extension of the
anterior adductor scar. Falsolucinoma n. gen. differs in the
absence of a regularly crenulate margin, the more foreward placed
umbones, the less asymmetric lunule and the much larger size.
Falsolucinoma leloeuffi (Cosel, 1989) n. comb. (Figs 7; 8)
Lucina leloeuffi Cosel, 1989: 315, 316, pl. 1, figs 1-3.
type mAteriAL. — Holotype: e Liberia, off Cap des Palmes, c.
4°10’n, 7°40’W, 250 m, dredged RV Reine Pokou, 13.X.1971, leg. Le
Loeuff (IRD), 1 lv. (MnHn).Paratypes: same locality, 2 lv.
(MnHn).
type LocALity. — Cap des Palmes, e Liberia, tropical West
Africa.
other mAteriAL exAmined. — cameroon. 1 spm (MnHn) taken by RV
Fridtjof Nansen during a cruise off the coast of Cameroon for FAo
purpose. Data of the specimen unknown.
distribution. — Gulf of Guinea, apparently from western Côte
d’Ivoire to Cameroon.
descriptionShell large, up to 56 mm long, length/height ratio
1.2, relatively thin-shelled, but solid, inequilateral, compressed,
subcircular-trian-gular-rostrate, slightly variable in outline and
length/height ratio. Beaks situated at or just behind the anterior
third of the valve. Anterior part triangular-rostrate, anterior
margin pointed. Posterior part broad, posterior margin obliquely
truncate. Postero-dorsal corner rather broadly rounded.
Antero-dorsal margin nearly straight, postero-dorsal margin
slightly convex. Ventral margin behind the anterior point slightly
concave, then to postero-ventral corner evenly rounded, this latter
narrowly rounded.
exterior with 10-15 conspicuous, prominent, thin, raised and
widely spaced commarginal lamel-lae: 15 in the holotype, 10 and 14
in the paratypes, which on the early and middle part of the valves
are evenly spaced, and may become slightly more closely spaced
ventrally. Interspaces smooth, with shallow commarginal growth
waves. Posterior area with a broad and shallow radial depression,
separated from the disk by a broadly rounded posterior angle.
Anterior area with a well marked and sharp radial depression,
ending in a sinuosity in the upper anterior margin. Anterior angle
nar-rowly rounded.
Hinge plate narrow, in the left valve with a small anterior
cardinal and a narrow lamellar posterior cardinal, a strong
anterior lateral and a narrow and long posterior lateral and above
both more or less strong, tooth-like reinforcements. Right valve
with a short, thick, bifid and only slightly inclined anterior
cardinal and a thin, oblique posterior cardinal. Two anterior
laterals with a deep depres-sion between them; lower lateral more
forward placed than upper lateral. Lower posterior lateral narrow
but rather strong, upper posterior lateral thin and much weaker.
Ligament short. Lunule very short and small, deeply sunken,
slightly asymmetric, escutcheon almost entirely filled by the
ligament. Adductor scars small, anterior scar with short, rather
narrow and somewhat taper-ing diverging part, pallial line meeting
the scar about in its middle. Inner margin of valves not visibly
and regularly crenulate but with shallow
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Fig. 7. — Falsolucinoma leloeuffi (Cosel, 1989) n. comb.: A,
holotype, off Cap des Palmes, E Liberia (c. 4°10’N, 7°40’W), 250 m,
lv., dredged RV Reine Pokou, leg. Le Loeuff, 13.X.1971, 55.3 mm
(MNHN), interior, exterior and dorsal view of lv.; B, paratype 1,
same locality, 54.3 mm (MNHN), interior and exterior of lv.; C,
paratype 2, same locality, 56.5 mm (MNHN), exterior of lv.; D, off
Cameroon (without any precision), trawled RV Fridtjof Nansen,
live-collected spm, 48.3 mm (MNHN), exterior and interior of lv.,
dorsal view.
radial waves on the zone between pallial line and margin and
sometimes a few vestiges of irregular crenulations.
Valves entirely white; periostracum rather strong,
almost white-translucent to pale straw-coloured or brownish,
often peeling off in the interspaces of the lamellae.
Measurements are provided in Table 3.
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Table 3. — Falsolucinoma leloeuffi (Cosel, 1989) n. comb.:
measurements (in mm) and length/height ratio. Non type specimen is
voucher specimen.
Shell length × height × tumidity Specimen Length/height
ratio56.5 × 45.0 Liberia, paratype 1.355.3 × 46.4 Liberia, holotype
1.254.3 × 46.6 Liberia, paratype 1.248.3 × 40.0 x 20.0 Cameroon
1.2
Fig. 8. — Falsolucinoma leloeuffi (Cosel, 1989) n. comb., half
schematic drawings of the insides of valves: A, holotype; B, C,
paratypes, all insides of lv.; D, spm from off Cameroon, inside of
rv. Scale bars: 10 mm.
remArksAs for the genus. The most similar looking species is
Lamellolucina jawa Taylor & Glover, 2002, from Madura,
Indonesia. It has a similar general shell shape, a similar hinge
dentition and also extremely small adductor scars but is
distinguished by the smaller size, the more circular outline, the
presence of a finely and regularly crenulate margin and
much more densely spaced commarginal lamellae. Falsolucinoma
leloeuffi n. comb. was described only from three right valves, but
fortunately now a single complete live-collected specimen, albeit
without any precise data, became available. It was trawled by the
RV Fridtjof Nansen in the Gulf of Guinea, apparently off Cameroon;
the known range is thus extended considerably eastward.
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Genus Afrolucina n. gen.
type And onLy species. — Afrolucina discontinua n. sp.
etymoLogy. — The name reflects that this genus was discovered on
the African shelf.
distribution. — Tropical West Africa.
diAgnosis. — Shells small, subcircular, slightly longer than
high, rather compressed. Beaks slightly in front of the vertical
midline. Surface with numerous fine and more or less densely spaced
commarginal lamellae, umbonal area appearing smooth. Interspaces
with very fine growth lines. Antero-dorsal angle very shallow,
anterior area well marked. Postero-dorsal area separated by a
rounded posterior angle. Lunule short, broad, markedly
asymmetrical, in the right valve broad, in the left valve very
narrow, sunken. escutcheon long, narrow and sunken. Hinge line
curved, hinge with one small, well defined cardinal tooth in the
right valve and two in the left valve. Anterior and posterior
lateral teeth in the right valve indistinct, in the left valve
almost obsolete. Anterior adductor scar rather elongate, with
diverging part about half its length or slightly shorter. Posterior
adductor scar small. Inner margins smooth.
remArksThis genus is most similar to a group of deeper water
lucinids from the Indo-Pacific discussed in detail by Cosel &
Bouchet (unpubl. data), which comprises some new genera, however,
none of them are really identical to Afrolucina n. gen. This
Indo-Pacific group has superficial resemblance to Lucinoma, but
that genus is characterized by the presence of well developed hinge
teeth and a long and slender diverging part of the anterior
adductor scar which meets the pallial line near the upper
(dorsalward) end of the impression. The species of the group here
discussed have a nearly edentulous hinge, whereas in the West
African Afrolucina discontinua n. gen., n. sp., small cardinals are
present. The spectacular lunular asymmetry indicates affinities of
Afrolucina n. gen. to the Myrtea group and is not seen as this in
the Indo-West Pacific genera. All genera, however, share a much
shorter and broader diverging part of the anterior adductor scar,
which is met by the pallial line in its middle, another character
of the Myrtea group.
The genus Tinalucina n. gen. is distinguished by the more tumid
valves, the more protruding um-
bones, the more regular commarginal sculpture, the more
equal-sized adductor scars with short and broad diverging part of
the anterior one, the less asymmetrical lunule and the smaller
shell size.
Afrolucina discontinua n. sp. (Figs 9-11)
type mAteriAL. — Holotype: Côte d’Ivoire, off Grand Bassam, 70
m, dredged RV Reine Pokou, 1977, leg. Le Loeuff (IRD), 1 fresh sh.
(MnHn).Paratypes: Abidjan region (no more precision), dredged RV
Reine Pokou, 1965-1974, leg. Le Loeuff, 2 sh., 1 juv. sh., 2 lv.
(MnHn); 1 sh., 1rv. (BMnH).
type LocALity. — Grand Bassam, Côte d’Ivoire.
etymoLogy. — This species is a good example of the several West
African species with a disjunct distribution, and that is expressed
in the name.
other mAteriAL exAmined. — senegal. Dakar, 14°43’n, 17°30’W,
205-230 m, dredged RV Gérard Tréca, 18.III.1958, leg. I.
Marche-Marchad, 1 rv., 1 lv. (MnHn). — 14°51.5’n, 17°30’W, 180-165
m, dredged RV Gérard Tréca, 18.III.1958, leg. I. Marche-Marchad, 1
rv., 2 lv., 1 fragm. (MnHn). — Baie de Gorée, 80-250 m, dredged RV
Gérard Tréca, 20.II.1956, leg. I. Marche-Marchad, 1 chipped lv.
(MnHn). — S of Gorée, 95-98 m, dredged RV Gérard Tréca, 18.II.1954,
leg. I. Marche-Marchad, 1 lv. (MnHn).liberia. near the border to
Côte d’Ivoire, 4°31.5’n, 8°31’W, 64 m, dredged RV Calypso,
20.V.1956, 1 lv., 1 rv. (MnHn).côte d’Ivoire. Abidjan region (no
precision), 100 m, dredged RV Reine Pokou, leg. Le Loeuff, 1 juv.
v. (MnHn). — 4°27.5’n, 7°09’W, 50 m, dredged RV La Rafale,
6.IV.1964, leg. G. Cherbonnier, 1 juv. rv. (MnHn). — off S. Pedro,
4°36’n, 6°33’W, 100 m, dredged RV La Rafale, 7.IV.1964, leg. G.
Cherbonnier, 1 spm (MnHn). — off Grand Bassam, 5°04.0’n, 3°45.8’W,
64 m, dredged RV Antéa, 16.VIII.1998, leg. R. von Cosel, 1 juv. lv.
(MnHn).equatorial Guinea. W of Bioko Island (formerly Fernando
Poo), off the coast of Cameroon, 3°50’20”n, 8°21’40”e, 98 m, in
silty bottom, taken by corer, Gardline Survey 2003, stn VIo 2, 1
juv. sh. (BMnH). — Same region, 4°01’16”n, 8°36’06”e, 70 m, taken
by corer, Gardline Survey 3003, stn neA-I, 1 juv. sh. (BMnH). —
Same region, 4°00’45”n, 8°24’15”e, 74 m, taken by corer, Gard-line
Survey 3003, stn BoC3FC, 1 juv. sh. (BMnH).congo (brazzaville).
n’Kossa oilfield, 5°53.12’S, 11°38.30’e, 200 m, leg. L. Bigot,
23.IX.1995, 1 rv. (MnHn).
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Fig. 9. — Afrolucina discontinua n. gen., n. sp.: A, holotype,
off Grand Bassam, Côte d’Ivoire, 70 m, dredged RV Reine Pokou, leg.
Le Loeuff, 1977, 17.4 mm (MNHN), interior and exterior of both v.;
B, two different dorsal views of holotype to show asymmetrical
lunule; C, paratype, Abidjan region, continental shelf (no
precision), 15.9 mm (MNHN), exterior of lv.; D, off Mussulo, Luanda
Province, Angola, 100 m, 14.7 mm, interior and exterior of rv.; E,
F, close-up photos of asymmetrical lunule in holotype.
Northern Angola. Ambrizete, 80 m, 1982-1986, leg. S. Gofas, 1
juv. rv. (MnHn). — Ilha de Luanda, 120 m, 1982-1986, leg. S. Gofas,
1 rv., 3 lv. (MnHn). — off Mussulo, 90-100 m, 1982-1986, leg. S.
Gofas, 1 rv. (MnHn). — Palmeirinhas, 60-80 m, 1982-1986, leg.
S. Gofas, 7 rv., 3 lv. (MnHn).Second morph, somewhat longer and
regular commarginal lamellae:bénin. off ouidah, 6°10’n, 2°05’e, 200
m, dredged RV Léon Coursin, 22.XI.1958, leg. I. Marche-Marchad,
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Cosel R. von
Fig. 10. — Afrolucina discontinua n. gen., n. sp., second
“morph”: A, off Ouidah, Bénin, 6°10’N, 2°05’E, 200 m, dredged RV
Léon Coursin, 14.1 mm, exterior and interior of rv.; B, off Ilha de
Luanda, N Angola, 120 m, 13.2 mm, interior and exterior of lv.; C,
off Niger delta, 4°05’N, 5°28’E, 90-105 m, dredged RV Calypso,
Golfe de Guinée, 1956, 15.0 mm, exterior and interior of lv.
3 rv., 2 lv. (MnHn).Nigeria. off niger delta, 4°05’n, 5°28’e,
90-105 m, dredged RV Calypso, 26.V.1956, 1 lv. (MnHn).Northern
Angola. Ilha de Luanda, 120 m, leg. S. Gofas, 1 lv. (MnHn).
distribution. — Senegal (Dakar); Côte d’Ivoire to inner Gulf of
Guinea (northern Cameroon, Bioko); northern Angola (Luanda). not
recorded from Guinea-Bissau to Liberia (border to Côte d’Ivoire)
and from southern Cameroon to the Congo Republic which may indicate
distribution gaps in the tropical zone proper.
descriptionShell 12-18 mm long, rather solid, somewhat variable
in outline and sculpture, subcircular (length/height ratio 1.1),
inequilateral, equivalve, compressed. Beaks just in front of the
vertical midline. Anterior margin with a slight but rather sharp
corner to the antero-dorsal margin. Antero-dorsal margin divided
into two short, concave to almost straight parts with a corner
between them, the upper part comprising the lunular area. Posterior
margin obliquely truncated, with rounded corners.
Postero-dorsal margin slightly convex. Ventral margin well
rounded.
exterior with numerous thin, more or less densely-spaced
commarginal lamellae, which are often eroded and which may be
obsolete on the first umbonal 10 mm of the valve, with surface
ap-pearing smooth. Interspaces with very fine growth lines.
Antero-dorsal area well separated, with denser commarginal lamellae
and wrinkles and a shallow radial depression in the middle.
Postero-dorsal area separated by a rounded posterior angle.
Hinge plate narrow, hinge with one small but generally distinct
oblique cardinal tooth in the right valve and two in the left
valve. Anterior and posterior laterals in the right valve appearing
as very small and indistinct knobs, in the left valve almost
obsolete. Lunule short and rather broad, markedly asymmetrical,
sunken; left valve with a strong and more or less protruding
lunular plate which inserts directly under the much narrower
lunular plate of the right valve into a socket under and parallel
to it (Fig. 9e, F). Anterior cardinal of
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Fig. 11. — Afrolucina discontinua n. gen., n. sp., half
schematic drawings of the insides of right valves: A, holotype; B,
paratype; C, juvenile specimen from Bioko (Fernando Poo),
4°01’16”N, 8°36’06”E, 70 m, Gardline Survey 2003 (BMNH). Scale
bars: A, B, 10 mm; C, 5 mm.
the left valve partly or completely integrated into the lunular
plate. escutcheon long, narrow and sunken. Anterior adductor scar
fairly small, with short ventral part separate from the pallial
line, this latter meeting the scar about in its middle or just
before it. Pallial line often divided into a line of close-set
separate impressions (Fig. 11B). Inner margin of valves smooth.
Colour of valves entirely white, periostracum very thin,
yellowish brown, on the earliest part of the valves thinner to
obsolete.
There exists a second “morph”, of which a few valves were
collected off Bénin, nigeria and off northern Angola (Fig. 10). The
valves have regular and rather densely spaced commarginal
lamellae
over the whole valve surface and are occasionally slightly more
elongate. As very little material is available, and as there might
be intergrades to the “normal” form, I leave them as a variety
within A. discontinua n. gen., n. sp.
Measurements are provided in Table 4.
biotopeIn soft sediment, most probably fine muddy sand, from 50
to about 230 m.
remArksIn outline, this species resembles somehow Graecina
karinae n. gen., n. sp. (see next entry) but is easily
distinguished by the sharp antero-dorsal corner, the
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Table 4. — Afrolucina discontinua n. gen., n. sp.: selected
measurements (in mm) and length/height ratio. All non type
specimens are voucher specimens.
Shell length × height × tumidity Specimen Length/height
ratio18.4 × 17.6 Côte d’Ivoire, paratype (MNHN) 1.017.4 × 16.1 ×
7.4 Côte d’Ivoire, holotype (MNHN) 1.117.4 × 15.6 Côte d’Ivoire,
paratype (BMNH) 1.115.9 × 14.3 Côte d’Ivoire, paratype (MNHN)
1.115.0 × 13.3 Nigeria, Calypso, 1956, stn 27 1.114.7 × 13.4
Angola, Mussulo 1.113.6 × 12.4 × 5.1 Côte d’Ivoire, Rafale, stn DR
17 1.113.6 × 12.3 × 5.2 Côte d’Ivoire, paratype (BMNH) 1.113.0 ×
11.4 × 4.5 Côte d’Ivoire, paratype (MNHN) 1.112.3 × 11.5 Liberia,
Calypso, 1956, stn 15 1.112.0 × 10.8 Senegal, Dakar, Gérard Tréca
1.110.1 × 9.3 × 3.7 Côte d’Ivoire, paratype (MNHN) 1.15.6 × 5.3 ×
2.4 Côte d’Ivoire, paratype (MNHN) 1.1
obliquely truncated posterior margin, the sculpture, the often
interrupted pallial line and the smaller size.
The distributional range of Afrolucina discontinua n. gen., n.
sp. coincides with the different zones of seasonal upwelling on the
coast of tropical West Africa: Senegal in the northern zone of
Alternance (see Intés & Le Loeuff 1984; Le Loeuff 1993; Le
Loeuff & Cosel 1998) with strong upwelling dur-ing northern
winter, Côte d’Ivoire and Bénin in the central atypical tropical
zone with intermittent seasonal upwelling and Angola in the
Southern zone of Alternance with upwelling in southern winter. The
species seems not to be present in the northern (Guinea to Liberia)
and southern (southern Cam-eroon to Gabon) typical tropical zones
and also not in the zones with weaker upwelling adjacent to the
zones of Alternance (Guinea-Bissau in the north and Congo in the
South). However, recently a few very small specimens were found
west of Bioko (Fernando Poo), which is already in the southern
typical tropical zone and within the influence of the niger delta.
The species may need some regular influence of upwelling.
Genus Graecina n. gen.
type And onLy species. — Graecina karinae n. sp.
distribution. — northern Angola (Ambrizete), tropical West
Africa.
diAgnosis. — Shells medium-sized, subcircular, slightly longer
than high, rather compressed. Beaks in front of the vertical
midline. Surface with thin commarginal lamellae or cords only on
the earlier part of the valves, becoming obsolete and then absent
ventrally. Rest of the valves with growth lines and some coarser
“growth stages”. Anterior area with two shallow radial depressions,
anterior angle indistinct. Postero-dorsal area indistinct and not
separated by a visible posterior angle. Lunule long, narrow,
slightly asymmetrical, sunken. escutcheon long, narrow and sunken,
delimited by a sharp and prominent, narrowly laminate keel, but no
long lamellate prolongations. Hinge arched, in the right valve with
one well developed cardinal tooth and sometimes the vestiges of a
posterior cardinal, and anterior and posterior laterals. Left valve
with two cardinals and well marked anterior and posterior laterals.
Anterior adductor scar rather elongate, with moderately long
diverging part, pallial line meeting the scar in about its middle
or just above it. Posterior adductor scar small. Inner margins
smooth.
etymoLogy. — The name goes back to Roman history as already does
the name of the type genus of Lucinidae, Lucina (Lucina is the
Roman goddess of childbirth). Lucina is believed to have been the
baptismal name of Pomponia Graecina, a noble Roman lady and wife of
the conqueror of Britain, Aulus Plautius. The new genus Graecina n.
gen. honours the same person as the genus Lucina.
remArksThis genus has an overall appearance of a large Myrtea;
especially with its raised and sharp escutcheonal keel, however,
the valves are much more compressed, and the anterior adductor
scars are more elongate, with a longer diverging part. In shell
form and outline
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and with the small posterior adductor scar, this genus looks
most similar to a new genus under description by Cosel &
Bouchet (unpubl. data), however, Graecina n. gen. is much larger,
has well defined cardinal and lateral teeth and commarginal
lamellae on the earlier part of the valves; the pallial line meets
the anterior adductor scar at a higher point and thus leaves a
longer ventral diverging part. Another genus, especially similar in
size and form of the anterior adductor is also under description by
Cosel & Bouchet (unpubl. data). In that genus, the hinge is
toothless, the hinge line is less bent and the lunule is
shorter.
Graecina karinae n. sp. (Figs 12; 13)
type mAteriAL. — Holotype: n Angola, Angola Margin, W of
Ambrizete, 7°18.42’S, 12°04.60’e, 360-367 m, trawled RV Thalassa,
ZAIAnGo BIoL 2, stn CP 09, 29.VIII.2000, leg. R. von Cosel, lv.
(MnHn).Paratypes: same locality, 3 rv., 1 lv. (MnHn); 2 rv.
(BMnH).
type LocALity. — Ambrizete, northern Angola, tropical West
Africa.
etymoLogy. — Dedicated to my colleague Karine olu-Le Roy from
IFReMeR, in acknowledgement of her longtime kind collaboration on
bivalves of cold seeps.
other mAteriAL exAmined. — Nigeria. S of Port Harcourt,
3°42.28’n, 7°47.59’W, 425 m, taken by corer, RV Le Suroît, stn
GuIneSS 2, 2.IX.1993, leg. P. Cochonat, 2 fossilized lv., 1 rv.
(MnHn).Northern Angola. Angola Margin, off Ambrizete, 7°18.42’S,
12°04.60’e, 360-367 m, trawled RV Thalassa, ZAIAnGo BIoL 2, stn CP
09, 29.VIII.2000, leg. R. von Cosel, associated specimens, 6 lv., 9
rv., all old and partly chipped or worn (MnHn).
distribution. — nigeria; northern Angola.
descriptionShell medium-sized, up to about 40 mm long, rather
thick and solid, somewhat variable in outline, subcircular
(length/height ratio 1.1), inequilateral, equivalve, rather
compressed. Beaks well in front of the vertical midline. Anterior
part broadly rounded, anterior margin evenly convex. Poste-rior
part rounded, posterior margin convex but
occasionally obliquely truncated, with rounded postero-ventral
corner. Antero- and postero-dorsal margins sloping, with a curved
hinge line; margin between the lunular area and the anterior margin
strongly curved. Postero-dorsal margin convex, occasionally more so
in its upper part behind the umbones. Ventral margin rounded, in
the middle less convex.
exterior with thin commarginal lamellae or cords, only on the
earlier third or fourth or sometimes the very earliest part of the
valves, becoming obsolete and then absent towards ventrally.
Interspaces with very fine growth lines only. Rest of the valves
with strong, dense and rather regular growth lines and some coarser
“growth stages”. Antero-dorsal area with two shallow radial
depressions, one closely under the lunular area, the other somewhat
more below it, anterior angle indistinct. Postero-dorsal area
indistinct and not separated by a visible pos-terior angle.
Hinge plate narrow and arched. Hinge in the right valve with one
well developed cardinal tooth and sometimes the vestiges of a
posterior cardinal, and long and narrow anterior and posterior
laterals. Left valve with one well developed cardinal and a narrow
and short anterior cardinal, and narrow, well marked anterior and
posterior laterals. Lunule rather long, narrow, slightly
asymmetrical, some-what broader in the right valve, sunken.
escutcheon long, narrow and sunken, delimited by a sharp, raised
and serrated keel, but no highly lamellate prolongations. Anterior
adductor scar rather small, long, with moderately long diverging
part, pallial line meeting the scar in about its middle or just
above it. Posterior scar small but rather broad. In-ner margin of
valves smooth.
Valves presumably white in life but in the dead collected
samples chalky or light greyish. Periostra-cum thin, light greenish
brown, when present.
Measurements are provided in Table 5.
biotopeAll collected specimens are rather aged single valves.
They were trawled, together with complete shells and/or valves of
two other lucinid species, also described herein (see below), on a
site at the Angola shelf margin (ZAIAnGo Program, site B) where
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Fig. 12. — Graecina karinae n. gen., n. sp.: A, holotype, Angola
Margin, W of Ambrizete, N Angola, 7°18.42’S, 12°04.60’E, 360-367 m,
trawled RV Thalassa, ZAIANGO BIOL 2, stn CP 09, leg. R. von Cosel,
29.VIII.2000, 31.8 mm (MNHN), interior, exterior and dorsal view of
lv.; B, paratype 1, same locality, 36.0 mm (MNHN), exterior and
interior of rv.; C, South of Port Harcourt, Nigeria, 3°42.28’N,
7°47.59’W, 425 m, RV Le Suroît, 23.1 mm, exterior and interior of
rv.; D, same locality, 26 mm, exterior and interior of lv.
about 20 to 45 m high, circular mounds of deep water coral
(Lophelia pertusa (Linnaeus, 1758)) are present (Dekindt et al.
2001; olu-Le Roy pers. comm.). on these mounds, living corals are
on top and on the higher parts, whereas dead corals and
debris are found on the lower part and at the bases. The lucinid
shells and valves were on the sediment around and in depressions
between the mounds. In the trawl, which had passed on an almost n-S
line just at the base of coral mounds in a depth of
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Table 5. — Graecina karinae n. gen., n. sp.: selected
measurements (in mm) and length/height ratio. All non type
specimens are voucher specimens.
Shell length × height (no tumidity) Specimen Length/height
ratio41.3 × 35.5 Angola, paratype (BMNH) 1.241.1 × 35.5 Angola,
paratype (MNHN) 1.239.6 × 34.6 Angola, paratype (MNHN) 1.139.4 ×
36.3 Angola, paratype (MNHN) 1.139.0 × 34.1 Angola, associated
specimen 1.137.9 × 32.8 Angola, associated specimen 1.236.0 × 32.2
Angola, paratype (MNHN) 1.131.8 × 27.7 Angola, holotype (MNHN)
1.131.6 × 26.2 Angola, associated specimen 1.230.4 × 26.7 Angola,
paratype (BMNH) 1.129.5 × 27.0 Angola, paratype (MNHN) 1.126.0 ×
21.4 Nigeria, Port Harcourt 1.223.1 × 19.0 Nigeria, Port Harcourt
1.2
Fig. 13. — Graecina karinae n. gen., n. sp., half schematic
drawings of the insides of valves: A, holotype, lv.; B, C,
paratypes, rv. Scale bars: 10 mm.
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Table 6. — Lucinoma vestita (Dautzenberg & Fischer, 1906):
measurements (in mm) and length/height ratio.
Shell length × height × tumidity Specimen Length/height
ratio15.8 × 15.0 × 6.2 Cape Verde Islands, syntype (MOM, figured)
1.114.7 × 13.7 × 6.0 Cape Verde Islands, syntype 2 (MOM) 1.112.9 ×
12.0 × 5.2 Cape Verde Islands, syntype 3 (MOM) 1.1
360-425 m, they came up as agglomerations of dead shells
embedded in dark grey and very sticky mud, but none of the lucinids
were collected alive or in very fresh state. Some valves had even
pieces of solidified mud on them, which were difficult to remove.
It is presumed that these Lucinidae species come from a site of
reducing sediments where fluid emissions (methane or sulfide-rich)
may still be slightly active or are no longer active, and where the
fauna is dying out.
remArksAs for the genus.
Genus Lucinoma Dall, 1901
type species. — Lucina filosa Stimpson, 1851, by original
designation.
species incLuded. — numerous species, worldwide.
diAgnosis. — Shells medium-sized to very large, rather thin to
strong and solid, very variable in outline, in general subcircular
to somewhat triangular, but also almost circular to even
short-oval. Anterior margin broadly rounded to more or less
pointed. umbones in front of the vertical midline. Surface with
more or less pronounced commarginal ribs or lamellae and finer
threads between them. Hinge with two well developed cardinal teeth
in each valve and a small anterior lateral and often a small
posterior lateral. Diverging part of the anterior adductor scar
very long and more or less narrow.
remArksLucinoma is one of the most speciose lucinid genera; it
is distributed worldwide, in tropical latitudes as well as in
temperate and cold waters. In tropical West Africa, four species
are known. More detailed comments on the genus will be given Cosel
& Bouchet (unpubl. data).
Lucinoma vestita (Dautzenberg & Fischer, 1906)
(Figs 14; 15A, B)
Phacoides (Lucinoma) vestita Dautzenberg & Fischer, 1906:
90-91, pl. 5, figs 1-5.
type mAteriAL. — Figured syntype: Cap Verde Islands, near Maio,
15°14’n, 23°04.1’W, 628 m, muddy sand, trawled RV Princess Alice,
14.VIII.1901, 1 complete sh. (MoM); same locality, 3 other
syntypes: 2 sh., 1 worn rv. (all MoM).
type LocALity. — Maio, Cape Verde Islands.
distribution. — only known from the Cape Verde Islands.
descriptionShell 12-16 mm long, thick and solid, subcircular,
inequilateral, equivalve, compressed. Beaks slightly in front of
the vertical midline. Anterior margin rounded, posterior margin
obliquely rounded-truncated with rounded corners. Postero-dorsal
margin slightly convex. Ventral margin evenly semicircular.exterior
with numerous, very fine, irregular growth lines, occasionally more
or less eroded on the um-bonal part of the valves; commarginal
lamellae only visible in the region of the posterior angle if at
all. earlier part of the valves appearing smooth. Posterior area
delimited by gently rounded posterior angle, anterior angle
absent.
Hinge plate very broad, especially under the umbones, with a
rather thin anterior and a strong posterior cardinal tooth in the
right valve and a strong, slightly bifid anterior and a thinner and
more laminar posterior cardinal in the left valve. Anterior
laterals in both valves small and knob-like but well defined,
posterior laterals ill-defined or obsolete. Lunule quite broad with
thick layer of periostracum. escutcheon long and narrow, liga-ment
deeply inset. Anterior adductor scar rather
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Fig. 14. — Lucinoma vestita (Dautzenberg & Fischer, 1906):
A, figured syntype, near Maio, Cap Verde Islands, 15°14’N,
23°04.1’W, 628 m, muddy sand, trawled RV Princess Alice,
14.VIII.1901, 15.8 mm (MOM), exterior of both v., dorsal view; B,
syntype 2, same locality, 14.7 mm (MOM), exterior and interior of
both v.; C, syntype 3, same locality, 12.9 mm (MOM), interior and
exterior of rv.
Measurements are provided in Table 6.
biotopeMuddy-sandy bottom on the shelf slope at about 600 m.
small, its diverging part very long and narrow. In-ner margin of
valves smooth.
Valves entirely white. Periostracum yellowish brown, on the
earliest parts of the valve thin to obsolete (eroded).
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Fig. 15. — Half schematic drawings of the insides of right
valves: A, B, Lucinoma vestita (Dautzenberg & Fischer, 1906);
A, figured syntype; B, syntype 2; C, D, Lucinoma atalantae n. sp.;
C, holotype; D, paratype 1. Scale bars: 10 mm.
remArksThis species is the smallest West African Lucinoma, it is
distinguished from the other Lucinoma of the region by the very
broad hinge plate under the umbones, which, together with the
concave lunular area, gives the beaks a more raised appearance.
Lucinoma atalantae n. sp. (Figs 15C, D; 16)
type mAteriAL. — Holotype: W of Mauritania, 20°32’n, 18°36’W,
2042 m, dredged RV Atalante, euMeLI 4, stn CP 16, 5.VI.1992, an
alcohol preserved spm (MnHn).Paratypes: same locality, 2 sh.
(MnHn).
type LocALity. — Cape Verde Basin, W of Cap Blanc,
Mauritania.
etymoLogy. — named after the RV Atalante, from which the type
material was taken.
other mAteriAL exAmined. — mauritania. W of Cap Blanc, 20°41’n,
18°33’W, 2114 m, dredged RV Atalante, euMeLI 2, stn CP 03,
5.II.1992, 3 spm, 1 adult, 1 juv. sh. (MnHn). — 20°33’n, 18°35’W,
2003 m, dredged RV Atalante, euMeLI 2, stn CP 04, 5.II.1992, 1 juv.
sh. (MnHn). — nW of Cap Blanc, 20°58.9’n, 18°13.6’W, 2112-2160 m,
RV Discovery, stn 9133#5, 25.II.1976, 2 spm, 2 sh. (BMnH). — Same
locality, 20°57.0’n, 18°11.0’W, 2110-2130 m, RV Discovery stn
11540, 2.IX.1987, 1 spm (BMnH).
distribution. — only known from the Cape Verde Basin.
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Fig. 16. — Lucinoma atalantae n. sp.: A, holotype, W of
Mauritania, 20°32’N, 18°36’W, 2042 m, dredged RV Atalante, EUMELI
4, stn CP 16, 5.VI.1992, 29.1 mm (MNHN), exterior and interior of
rv., exterior and interior with soft parts of lv., dorsal view; B,
paratype 1, same locality, 29.1 mm (MNHN), interior and exterior of
lv.; C, paratype 2, same locality, 26.7 mm (MNHN), interior of both
v.
rounded, posterior margin more or less conspicuously truncated,
occasionally slightly sinuous, with rounded corners. Ventral margin
convex, nearly semi-circular. Beaks just in front of the vertical
midline.
descriptionShell to 29 mm long, rather solid, variable in
outline and sculpture, subcircular (length/height ratio between 1.1
and 1.2), compressed. Anterior margin rather narrowly
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832 ZOOSYSTEMA • 2006 • 28 (4)
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Table 7. — Lucinoma atalantae n. sp.: measurements in mm and
length/height ratio. All non type specimens are voucher
specimens.
Shell length × height × tumidity Specimen Length/height
ratio31.7 × 28.5 × 13.7 Mauritania, Discovery, stn 9133#5 1.129.1 ×
24.9 × 11.6 Mauritania, holotype 1.229.0 × 24.6 × 9.5 Mauritania,
paratype 1 1.228.7 × 24.1 × 11.1 Mauritania, Discovery, stn 11540
1.227.0 × 23.7 × 10.2 Mauritania, EUMELI 2, stn CP 03 1.126.7 ×
24.1 × 11.4 Mauritania, paratype 2 1.125.1 × 21.0 × 9.7 Mauritania,
EUMELI 2, stn CP 03 1.220.3 × 18.9 × 8.4 Mauritania, EUMELI 2, stn
CP 03 1.111.7 × 10.3 × 4.4 Mauritania, EUMELI 2, stn CP 04 1.111.3
× 9.8 × 3.8 Mauritania, EUMELI 2, stn CP 03 1.210.7 × 9.0 × 3.7
Mauritania, EUMELI 2, stn CP 03 1.210.5 × 9.0 × 3.4 Mauritania,
Discovery, stn 9133#5 1.2
exterior with numerous, very fine, irregular growth lines and
commarginal lamellae which in juvenile specimens are very close-set
and evenly spaced, in adult and subadult specimens they are more
irregu-larly and wider spaced, obsolete or entirely missing.
earlier part of the valves often eroded. Posterior area delimited
by gently rounded posterior angle, anterior angle absent. Lunule
sunken, with rather thick layer of periostracum on it. escutcheon
long and very narrow, ligament slightly sunken.
Hinge plate moderately broad, with two well devel-oped cardinal
teeth in each valve; posterior cardinal in the left valve rather
thin and laminar. Laterals more or less indistinct. Diverging part
of anterior adductor scar long. Inner margin smooth.
Valves white. Periostracum very strong, yellow-ish brown, on the
earliest parts of the valve thinner to obsolete.
Measurements are provided in Table 7.
biotopeIn soft sediment, most probably mud, found between 2003
and 2160 m.
remArksLucinoma atalantae n. sp. is distinguished from L.
vestita, the most similar species, by its larger size, the thinner
and slightly longer valves, the narrower hinge plate and the
sculpture. Lucinoma atalantae n. sp. shows dense commarginal
lamellae on the earlier part of the valve whereas L. vestita is
smooth. Juveniles of L. atalantae n. sp. are closer
in outline to L. vestita but the narrower hinge line and the
presence of commarginal lamellae remain distinguishing features.
Both species have a different depth preference: L. vestita on the
shelf slope at about 600 m, L. atalantae n. sp. much deeper, at
about 2000 m. The two species have been taken at their type
localities only, and we do not know their actual distribution
range. Apart from an Indo-West Pacific species (under description
by Cosel & Bouchet) which was found at 2570 m, L. atalantae n.
sp. is the deepest-recorded lucinid species.
Lucinoma myriamae n. sp. (Figs 17; 18A)
type mAteriAL. — Holotype: n Angola, Angola margin, W of
Ambrizete, 7°18.42’S, 12°04.60’e, 360-367 m, BIoZAIRe Program site
ZB-B, trawled RV Thalassa, ZAIAnGo BIoL 2, stn CP 09, 29.VIII.2000,
leg. R. von Cosel, a complete shell (MnHn).Paratypes: same
locality, 1 rv., 3 lv. (MnHn); 1 rv., 1 lv. (BMnH).
type LocALity. — Ambrizete, northern Angola, tropical West
Africa.
etymoLogy. — Dedicated to my collegue Myriam Sibuet, principal
investigator of the ZAIAnGo BIoL and BIoZAIRe program and cruise
leader of ZAIAnGo BIoL 2, in which the author participated and in
which the species was taken.
other mAteriAL exAmined. — Nigeria. S of Port Harcourt,
3°42.28’n, 7°47.59’W, 425 m, taken by corer, RV Le Suroît, GuIneSS
2, stn KG 2 n 11, 2.IX.1993,
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Fig. 17. — Lucinoma myriamae n. sp.: A, holotype, Angola Margin,
W of Ambrizete, N Angola, 7°18.42’S, 12°04.60’E, 360-367 m, trawled
RV Thalassa, ZAIANGO BIOL 2, stn CP 09, leg. R. von Cosel,
29.VIII.2000, 51.2 mm (MNHN), exterior and interior view of both
v., dorsal view; B, juvenile specimen, 20.5 mm, exterior of lv.; C,
S of Port Harcourt, Nigeria, 3°42.28’N, 7°47.59’E, 425 m, RV Le
Suroît, specimen from piston corer, in solidified mud, 42.5 mm,
exterior of lv., dorsal view; D, paratype 1, 50.5 mm (MNHN),
exterior of lv.
leg. P. Cochonat, 1 sh. with “fossilized” hardened mud between
valves (MnHn).Gabon. SW of Port-Gentil, 1°35.60’S, 8°34.69’e, 410
m, boxcorer, RV Le Suroît, GuIneSS 2, stn GGS 2 G10,
25.VIII.1993, leg. P. Cochonat, 1 lv. (MnHn).Northern Angola. W
of Ambrizete, 7°18.42’S, 12°04.60’e, 360-367 m, trawled RV
Thalassa, ZAIAnGo BIoL 2, stn CP 09, 29.VIII.2000, leg. R. von
Cosel, associated
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Table 8. — Lucinoma myriamae n. sp.: measurements (in mm) and
length/height ratio. Non type specimens are voucher specimens.
Shell length × height × tumidity Specimen Length/height
ratio53.6 × 48.9 Angola, paratype (BMNH) 1.151.2 × 46.7 × 31.3
Angola, holotype 1.150.5 × 47.1 Angola, paratype (MNHN) 1.150.1 ×
47.0 Angola, paratype (BMNH) 1.143.5 × 42.2 Angola, paratype (MNHN)
1.042.5 × 38.1 × 23.4 Nigeria, Port Harcourt 1.134.5 × 31.0 Angola,
paratype (MNHN) 1.133.2 × 29.6 Angola, paratype (MNHN) 1.120.5 ×
17.5 Angola, ZAIANGO BIOL 2, stn KGS 20 1.2
specimens: numerous rv. and lv. in part more or less worn
(MnHn). — W of Ambrizete, 7°18.38’S, 12°04.72’e, 363 m, taken by
boxcorer, RV Thalassa, ZAIAnGo BIoL 2, stn KGS 20, 29.VIII.2000,
leg. R. von Cosel, 1 juv. lv. (MnHn). — Same locality, 7°18.31’S,
12°04.82’e, 371-375 m, taken by RoV Victor, RV Atalante, BIoZAIRe
1, stn PL 79-3, 6.I.2001, leg. M. Sibuet, 1 sh. (MnHn).
distribution. — Gulf of Guinea: nigeria to northern Angola.
descriptionShell to about 53 mm long, thick and solid, some-what
variable in outline, subcircular-triangular (length/height ratio
mostly 1.1), rather inflated. Anterior part tapering, anterior
margin narrowly and obliquely truncated, antero-ventral margin
almost straight to straight. Posterior margin broadly
rounded-truncated, with rounded corners. Ventral margin convex,
more so in the middle than antero-and postero-ventrally.
Antero-dorsal (lunular) margin straight to slightly concave,
postero-dorsal margin convex. Beaks in front of the vertical
midline.exterior with strong, rather regularly and widely spaced
commarginal lamellae which on the earlier parts of the valves are
finer and closer-set and which are obsolete on the anterior area.
Interspaces with numerous, densely spaced, somewhat irregular
commarginal cords, becoming obsolete on the very early parts of the
valves which may be eroded. Anterior area delimited by a rounded
anterior angle, posterior area by a rounded and indistinct
posterior angle. Lunule rather long and broad, sunken, with rather
thick layer of periostracum on it. escutcheon long and very narrow,
delimited by a sharp keel, ligament sunken.
Hinge plate strong, moderately broad, with two well developed
cardinals in each valve; posterior
cardinal in the left valve thinner than the others. Anterior and
posterior lateral in the right valve present as strong and well
distinct knobs. Left valve with two strong anterior laterals and
one weaker posterior lateral. Diverging part of the anterior
adductor scar long and narrow. Inner margin smooth but ventral part
of the inner surface, especially between mantle line and margin,
with strong radial undulations.
Valves whitish in life, periostracum rather thin and dirty
brownish.
Measurements are provided in Table 8.
biotopeno live specimens found. on sticky mud near mounds of
Lophelia pertusa near reducing sediments (for details see Graecina
karinae n. gen., n. sp.), shells and valves found between 360-425
m.
remArksTwo “morphs” of this variable species can be
distin-guished: the morph on which the type lot is based (Figs 17;
18A), with rounded-triangular outline, and another, higher and more
rounded morph with more dense commarginal sculpture (Figs 18B; 19),
which is covered separately in the next entry. All kinds of
intergrades occur between these two morphs, therefore, there is no
separation on species level.
Lucinoma myriamae n. sp. (second morph) (Figs 18B; 19)
mAteriAL exAmined. — Northern Angola. W of Am-brizete,
7°18.42’S, 12°04.60’e, 360-367 m, trawled RV Thalassa, ZAIAnGo BIoL
2, stn CP 09, 29.VIII.2000,
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Table 9. — Lucinoma myriamae n. sp. (second morph): selected
measurements (in mm) and length/height ratio (all from type
locality).
Shell length × height × tumidity Specimen Length/height
ratio55.2 × 50.6 Angola, ZAIANGO BIOL 2, stn CP 09 1.154.3 × 52.5
Angola, ZAIANGO BIOL 2, stn CP 09 1.053.0 × 54.2 Angola, ZAIANGO
BIOL 2, stn CP 09 1.052.6 × 48.6 Angola, ZAIANGO BIOL 2, stn CP 09
1.152.0 × 53.2 Angola, ZAIANGO BIOL 2, stn CP 09 1.051.0 × 47.8
Angola, ZAIANGO BIOL 2, stn CP 09 1.149.3 × 49.1 Angola, ZAIANGO
BIOL 2, stn CP 09 1.048.2 × 44.7 Angola, ZAIANGO BIOL 2, stn CP 09
1.147.5 × 48.1 × 31.1 Angola, ZAIANGO BIOL 2, stn CP 09 1.047.1 ×
46.6 × 30.1 Angola, ZAIANGO BIOL 2, stn CP 09 1.047.0 × 44.1 × 34.7
Angola, ZAIANGO BIOL 2, stn CP 09 1.142.4 × 38.5 Angola, ZAIANGO
BIOL 2, stn CP 09 1.138.3 × 36.3 × 22.2 Angola, BIOZAIRE 1, PL 79-3
1.131.2 × 28.5 Angola, ZAIANGO BIOL 2, stn CP 09 1.1
leg. R. von Cosel, 3 sh., numerous rv. and lv. in part more or
less worn (MnHn). — W of Ambrizete, 7°18.31’S, 12°04.82’e, 371-375
m, taken by RoV Victor, RV Atalante, BIoZAIRe 1, stn PL 79-3,
6.I.2001, leg. M. Sibuet, 1 sh., several v. and fragments, more or
less worn (MnHn). — Same locality, 7°17.78’S, 12°02.66’e, 372-408
m, taken by RoV Victor, RV Atalante, BIoZAIRe 1, stn PL 77-1,
5.I.2001, leg. M. Sibuet, several mostly worn v. (MnHn).
descriptionShell to 53 mm long, thick and solid, variable in
outline, subcircular (length/height ratio between 1.0 and 1.2),
inflated. Anterior margin broadly rounded, with an indistinct
truncation, antero-ventral margin almost more or less rounded.
Posterior margin broadly rounded-truncated, with rounded corners.
Ventral margin well convex. Antero-dorsal (lunular) margin straight
to slightly concave, postero-dorsal margin convex. Beaks slightly
in front of the vertical midline.
exterior with rather densely to more widely spaced commarginal
lamellae and on the interspaces with numerous, strong and dense,
more or less irregular commarginal cords, becoming obsolete on the
very early parts of the valves which may be eroded. An-terior area
delimited by a rounded anterior angle, posterior area by a rounded
posterior angle and often marked by a shallow to indistinct
indentation of the posterior margin. Lunule and hinge dentition as
in the “normal” morph.
Measurements are provided in Table 9.
remArksThis “morph” is distinguished from the type series by its
shorter, higher and more rounded shells with much denser
commarginal lamellae. The shells are often more tumid. There are
all kinds of intermediates to the “normal morph”. Lucinoma myriamae
n. sp. with its two morphs shows well the plasticity of species of
Lucinoma at a single locality. The nominate “morph” could be
com-pared with Lucinoma species from the Indo-West Pacific of which
one (under description by Cosel & Bouchet, unpubl. data) has
the same outline and ornamentation.
A close-looking species is Lucinoma kazani Salas & Woodside,
2002, found live in the eastern Mediter-ranean in a cold seep area
on mud volcanoes in the Anaximander Mountains at 1165-1854 m depth
S of Turkey (Salas & Woodside 2002). However, L. kazani is
smaller (up to 38.4 mm length), less high and has finer commarginal
cords, also with strong and irregular growth lines between them
(see Fig. 18C). The diverging part of the anterior adductor scar is
somewhat broader and shorter as in L. kazani. The other large
Atlantic species, L. borealis (Linnaeus, 1767) (northern norway to
Cap Blanc, Mauritania and throughout the Medi-terranean), is more
circular, slightly smaller (on the West African coast to a length
of 40 mm), in average less tumid and, in contrast to L. myriamae n.
sp., it has more densely spaced irregular commarginal ridges or
lamellae.
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836 ZOOSYSTEMA • 2006 • 28 (4)
Cosel R. von
Fig. 18. — Half schematic drawings of the insides of right
valves: A, B, Lucinoma myriamae n. sp.; A, holotype; B, second
morph, N Angola, from type locality; C, Lucinoma kazani Salas &
Woodside, 2002, Kazan Mud Volcano, Anaximander Mountains, eastern
Mediterranean, holotype (MNHN) (for comparison). Scale bars: 10
mm.
An interesting fact is the similar distribution pat-terns of the
cold seep species pairs Lucinoma kazani-L. myriamae n. sp. and
Isorropodon perplexum-I. bigoti (Vesicomyidae, see Cosel &
Salas 2001), of which one species lives on the seeps in the eastern
Mediter-ranean and the other species off northern Angola.
Genus Anodontia Link, 1807
type species. — Anodontia alba Link, 1807, by original
designation.
species incLuded. — 25 species (Taylor & Glover 2005),
worldwide.
diAgnosis. — Shells small to very large, equivalve,
inequilateral, very tumid to globose, thin to moderately thick,
circular to subcircular, with more or less protruding umbones.
Hinge plate very narrow, toothless, ligament plate horizontal to
shell margin or slanting towards the interior of the valve. Surface
smooth, with more or less pronounced irregular growth lines and
stages. Anterior adductor scar small, with comparatively short and
small diverging part.
remArksA detailed worldwide revision of the genus has recently
been published by Taylor & Glover (2005). The subgeneric
classification followed here is also treated therein.
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new taxa of tropical West African Lucinidae (Mollusca,
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ZOOSYSTEMA • 2006 • 28 (4)
Fig. 19. — Lucinoma myriamae n. sp., second morph: A, a typical
specimen, 47.1 mm, interior and exterior of both v., dorsal view;
B, another specimen, 47.5 mm, exterior of both v., both from type
locality.
Subgenus Afrophysema Taylor & Glover, 2005
Anodontia (Afrophysema) chevalieri Cosel in Taylor & Glover,
2005
(Figs 20; 21A, B)
Anodontia (Afrophysema) chevalieri Cosel in Taylor & Glover,
2005: 308, figs 10A, 12A, 24e-H, 25.
type mAteriAL. — Holotype: Gabon, Port-Gentil, Banc du Prince,
0°36.1’S, 8°48.1’e, 5-9 m, a complete shell (MnHn).
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838 ZOOSYSTEMA • 2006 • 28 (4)
Cosel R. von
Table 10. — Anodontia (Afrophysema) chevalieri Cosel in Taylor
& Glover, 2005: selected measurements (in mm) and length/height
ratio. All non type specimens are voucher specimens.
Shell length × height × tumidity Specimen Length/height
ratio42.1 × 38.0 × 30.0 Gabon, holotype (MNHN) 1.141.3 × 35.0 ×
31.8 Gabon, paratype (MNHN) 1.235.8 × 33.7 × 28.4 Gabon, paratype
(MNHN) 1.135.0 × 31.1 × 22.2 Gabon, paratype (BMNH) 1.133.6 × 29.5
× 25.4 Gabon, paratype (MNHN) 1.130.5 × 28.5 × 21.7 Côte d’Ivoire,
Abidjan (leg. Le Loeuff) 1.129.4 × 26.1 × 20.0 Côte d’Ivoire,
Abidjan (leg. Le Loeuff) 1.127.5 × 24.3 × 16.7 Gabon, Port-Gentil,
associated specimen 1.126.5 × 23.8 × 17.4 Gabon, Port-Gentil,
associated specimen 1.125.4 × 23.1 × 16.2 Côte d’Ivoire, Abidjan
(leg. Le Loeuff) 1.125.0 × 21.5 × 15.7 Gabon, Port-Gentil,
associated specimen 1.223.3 × 21.4 × 15.7 Gabon, Port-Gentil,
associated specimen 1.1
Paratypes: same locality, 1980-1989, leg. C. Chevalier, 3 sh.
(MnHn); 1 sh. (BMnH 20040252).
type LocALity. — Port-Gentil, Banc du Prince, a shoal ene of Cap
Lopez, Mandji Peninsula, Gabon.
other mAteriAL exAmined. — côte d’Ivoire. Conti-nental shelf in
Abidjan region (no details), trawled RV Reine Pokou, 1975-1977,
leg. P. Le Loeuff, 4 sh., 1 juv. sh., 1 lv. (MnHn).benin. ouidah
[Wydah], 6°10’n, 2°05’e, 200 m, dredged RV Léon Coursin, leg I.
Marche-Marchad, 1 rv. (MnHn). — 6°05’n, 2°15’e, 180-320 m, trawled
RV Thierry, Guinean Trawling Survey, stn 35/7, leg. G. Cherbonnier,
4.X.1963, 1 rv., 2 lv. (MnHn).Gabon. Port-Gentil, Banc du Prince,
0°36.1’S, 8°48.1’e, 5-9 m, 1980-1989, leg. C. Chevalier, 7
associated speci-mens (sh.) (MnHn).
distribution. — only known from Côte d’Ivoire, Bénin and
Gabon.
descriptionShell to 42 mm long, rather thin but solid,
equi-valve, inequilateral, very inflated, quite-vari-able in
outline, more or less longer than high, subcircular to short-ovoid,
length/height ratio 1.1. umbones prominent, well protruding over
the dorsal margin, directed forward, beaks well in front of the
vertical midline. Anterior part short, anterior margin with a
rather broadly rounded antero-dorsal corner, towards ventrally
convex. Ventral margin well rounded and evenly convex. Posterior
part broad, posterior margin well rounded, postero-dorsal corner
indistinct, no postero-ventral corner.
exterior without regular sculpture and only with coarse and very
irregular growth lines and wrin-kles and more pronounced growth
stages. A few shallow, very broad and indistinct radial waves are
also visible, especially under certain angle of view. Anterior and
posterior angle absent. Lunule small and short, more or less
narrow, almost symmetric, not sunken; escutcheon absent.
Ligament moderately long, broad, partly hidden by the
postero-dorsal margin but not very deep sunken, on a broad nymph,
which is obliquely, nearly “vertically” tilted towards the interior
of the valves; therefore ligament and hinge plate appearing narrow
at a horizontal view of the valve inside, full width of the
ligament only visible from ventrally. In smaller specimens,
ligament may be less broad.
Hinge plate very narrow and toothless. Anterior adductor scar
small, with a rather narrow diverg-ing part, the pallial line
meeting the scar above its middle, occasionally at one third the
length of the scar. Posterior adductor scar very small. Anterior,
ventral and posterior margin on the inner side slightly,
irregularly and very finely dentate, but on the very edge
smooth.
Valves pure white. Periostracum very thin, pale straw coloured
and mostly eroded.
Measurements are provided in Table 10.
biotopeIn muddy-sandy bottom on the deeper shelf, ap-parently
only in the Port-Gentil region of Gabon occurring shallower, from
about 5 m downwards.
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ZOOSYSTEMA • 2006 • 28 (4)
Fig. 20. — Anodontia (Afrophysema) chevalieri Cosel in Taylor
& Glover, 2005: A, holotype, Port-Gentil, Gabon, Banc du
Prince, 0°36.1’S, 8°48.1’E, 5-9 m, leg. C. Chevalier, 1980-1989,
42.1 mm (MNHN), exterior and interior of rv., exterior of lv.; B,
paratype 1, same locality, 41.3 mm (MNHN), interior and exterior of
both v., dorsal view.
remArksThis species is characterized by its very inflated shell,
the broad ligamental nymph which is slanting towards the interior
of the valve and the slightly dentate inner margin. A similar and
possibly
sibling species is Anodontia eutornus (Tomlin, 1921) from the
Indian ocean coast of South Africa, Se Africa and Se Madagascar,
described as Cryptodon eutornus by Tomlin (1921: 215, pl. 8, fig.
5). It has the same typical ovoid shell form
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840 ZOOSYSTEMA • 2006 • 28 (4)
Cosel R. von
Fig. 21. — Half schematic drawings of the insides of valves: A,
B, Anodontia (Afrophysema) chevalieri Cosel in Taylor & Glover,
2005; A, holotype, rv.; B, paratype 1, rv.; C, D, Anodontia
(Loripinus) senegalensis Cosel in Taylor & Glover, 2005, off
Cap Blanc, 20°34’N, 17°47’W, 90 m, trawled RV Président Théodore
Tissier; C, lv.; D, rv. Scale bars: 10 mm.
and exceptional tumidity as Anodontia chevalieri but is still
larger. Although that species had been well recognized by Barnard
(1950: 181, pl. 28, fig. 5) with a figure of a typical specimen, in
more recent works on South African molluscs, it was always mistaken
for or synonymized with A. edentula (Linnaeus, 1758) (Barnard 1964;
Kilburn & Rippey 1982; Steyn & Lussi 1998). This is
additional evidence for the close affinity of the West African
marine molluscan fauna with the Indo-Pacific, especially with the
Indian ocean. For further details, see Taylor & Glover
(2005).
Subgenus Loripinus Monterosato, 1883
Anodontia (Loripinus) senegalensis Cosel in Taylor & Glover,
2005
(Figs 21C, D; 22)
Anodontia (Loripinus) senegalensis Cosel in Taylor & Glover,
2005: 326, figs 11B, 12B, 42F-I, 43.
type mAteriAL. — Holotype: Senegal, S of Gorée, 110-112 m, lv.,
dredged RV Gérard Tréca, leg I. Marche-Marchad, 18.II.1954
(MnHn).Paratypes: Dakar region, 14°50.2’n, 17°29.5’W, 150 m,
dredged RV Tenace, 15.III.1967, leg. I. Marche-Marchad, 2 rv.
(MnHn); 1 lv. (BMnH 20040238).
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ZOOSYSTEMA • 2006 • 28 (4)
Table 11. — Anodontia (Loripinus) senegalensis Cosel in Taylor
& Glover, 2005: selected measurements (in mm) and length/height
ratio. All non type specimens are voucher specimens.
Shell length × height (no tumidity) Specimen Length/height
ratio36.6 × 32.1 Mauritania, Cap Blanc, Président Théodore Tissier
1.131.0 × 27.0 Mauritania, Cap Blanc, Président Théodore Tissier
1.129.5 × 25.6 Mauritania, Cap Blanc, Président Théodore Tissier
1.227.5 × 24.0 Mauritania, Cap Blanc, Président Théodore Tissier
1.124.4 × 21.1 Mauritania, Cap Blanc, Président Théodore Tissier
1.223.3 × 21.1 Mauritania, Cap Blanc, Président Théodore Tissier
1.120.8 × 18.2 Se